1. Field of the Invention
The present invention relates to a constant velocity universal joint for use in any application requiring torque transmission through a varying angle. More particularly, the invention involves a universal joint with an outer race member that has an annular recess with a plurality of equally spaced grooves therein. An inner race member is positioned within the annular recess of the outer race member. The end of the inner race member that is positioned in the annular recess of the outer race member contains a plurality of circumferentially spaced spherical balls which roll in the plurality of grooves of the outer race member. The exterior surface of each spherical ball rests against an axially aligned pin which is mounted integral with the inner race member.
2. Description of the Prior Art
The prior art reveals a wide variety of devices for the transmission of torque through an angle. In general, most of the prior art devices utilize an outer member with an inner member positioned therein. Either spherical balls or modified cylindrical roller bodies are positioned between the outer and inner members to facilitate articulation of the device.
The present invention is an improvement over the constant velocity universal joint described in U.S. patent application Ser. No. 945,183, filed Dec. 23, 1986, which is a file wrapper continuation of Ser. No. 704,196 filed Dec. 22, 1985, assigned to GKN Automotive Components Inc., and entitled "Constant Velocity Universal Joint and Apparatus Embodying the Same," hereinafter referred to as the CV universal joint. The above referenced prior art disclosed constant velocity universal joints for connecting drive and driven members when the members are in high speed operation, offset at an angle, or have misalignment between the members. The universal joint has an outer race member with an inner race member positioned therein. A plurality of spherical balls are positioned in an aperture in the inner race member and engage grooves that are positioned in the interior of the outer race member. The spherical balls contact one another, thus, providing mutual support for each other inwardly of the inner race member towards the center of the joint. A quick disconnect version of the invention that employs a centrally located movable pintle is also shown.
A constant velocity universal joint shown and described in U.S. Pat. No. 3,802,221 entitled "Constant Velocity Universal Joint" and issued Apr. 9, 1974, to Kei Kimata, shows an outer member with an axially aligned enlarged bore therein. One end of the enlarged bore is dimensioned so as to accommodate one end of a torque member. The other end of the enlarged bore is of reduced diameter so that a cantilevered central shaft can be fixedly positioned therein. The cantilevered central shaft is axially positioned and occupies part of the volume of the enlarged portion of the axially aligned bore. A torque member with a hollow end has radially disposed bores so as to accommodate a plurality of spherical balls in the bores. During assembly of the universal joint, the torque member is installed into position so that the cantilevered central shaft carried by the outer member is positioned within the center of the plurality of spherical balls. The structure forming the hollow end of the torque member and the spherical balls carried therewith occupy the space between the cantilevered central shaft and the inside surface of the bore of the outer member.
U.S. Pat. No. 4,156,354 entitled "Angularly Flexible Cardan Shaft Joint" and issued May 29, 1979, to Werner Krude, shows a high speed, high-torque transmitting universal joint where the torque is transmitted through chamfered roller bodies interposed between inner and outer joint members wherein the roller bodies are equidistantly spaced circumferentially of the joint assembly, with each roller body being received in planar recesses in the inner joint member for radially slidable engagement relative thereto. The above described universal joint increases the complexity and size of the joint and requires close maintenance of surface finish and other manufacturing tolerances. Because of these reasons and the increased friction resulting from the sliding relationship of the planar surfaces, this type of joint has decreased smoothness of operation while at the same time having increased manufacturing costs.
One embodiment, particularly depicted in FIGS. 3 and 4 of the drawings, shows a torque transmitting shaft with a bulbous end that has an axially positioned bore. An elastomeric block or pad is positioned in the central space between the roller bodies, however, the block or pad is a non-load carrying member, hence, it functions in a manner which does not affect the actual joint function of the overall assembly.
Thus, it can be observed that the utilization of a centrally positioned block or pad within the bulbous end of the torque transmitting shaft does not enhance the load carrying capabilities of the universal joint nor does it decrease the friction that results because of the sliding relationship of the planar surfaces. For the above set forth reasons, the centrally positioned block or pad provides a less than satisfactory solution to the problem of torque transmission.